.bkgd-dark

.bkgd-grey .bkgd-gray

.bkgd-light

40% opacity (Title bars)

.bkgd-grid40 .bkgd-grid

30% opacity (Unused)

.bkgd-grid30

20% opacity (Unused)

.bkgd-grid20

10% opacity (Surroundings)

.bkgd-grid10 .bkgd-surround

Transparent

.bkgd-transparent